Corrugated pallet

ABSTRACT

A corrugated paper pallet formed from stringers, a top sheet and a bottom sheet. Each stringer is formed from an identical blank which is die cut to form four flaps. Four fold lines are impressed into the corrugated and the blank folded to form a rectangular box section with a double layer on one side. The flaps are folded to close off sections of the box sections and form openings through which lines may be passed. Top and bottom are adhered to parallel stringers. The pallet requires no fumigation, may be coated to resist grease, water or moisture, and the entire pallet is easily recycled

FIELD OF THE INVENTION

This invention relates to high strength recyclable pallets made from corrugated paper.

BACKGROUND OF THE INVENTION

Corrugated paper dates to the mid-19^(th) century and corrugated paper for shipping pallets dates to the early 1970's in Japan. Most are based upon multiplying folded corrugated sheets to approximate the wooden stringers of conventional pallets. Wozniacki, U.S. Pat. No. 5,184,558 and Hutchison, U.S. Pat. No. 5,568,774 are representative. Such construction is suitable for most pallets used for shipping consumer items but is difficult to assemble without expensive automation and also difficult to ship in knock-down form.

Corrugated pallets have many advantages. Unlike wooden, plastic, or metal pallets, corrugated can be recycled at the recipient's location as paper/cardboard and does not have to be returned for reuse. Even so called “pallet pools” ship a lot of air.

Exported pallets pose two problems. Return is nearly impossible and the International Plant Protection Convention, as well as local laws in the EU, China and Australia effectively implement a ban on wood pallets which have not been certified to be fumigated by heat or pressure treatment with chemicals. Corrugated pallets, because of their processing, do not require fumigation and offer clear cost advantages in foreign shipping.

There exists a need for simple corrugated pallet designs which are strong but do not require expensive multiple-step die cutting and folding steps, do not require excessive adhesive to assemble and which can be assembled at the user's site by minimally skilled laborers.

BRIEF DESCRIPTION OF THE INVENTION

It is a first objective of this invention to provide a strong, stiff, price-effective pallet which is durable within the needs of the user.

It is a second objective of this invention to provide a corrugated pallet which can be shipped to the user in a knocked-down form and easily assembled on site with minimal tools.

It is a fourth objective of this invention to provide a corrugated pallet requiring minimal investment in equipment for the making of components and for assembly.

It is a fifth objective of this invention to provide a corrugated pallet which is capable of four-way entry by fork lifts and pallet trucks.

It is a sixth objective of this invention to provide a corrugated pallet which fits the Uniform Freight Industry Standards Classification Standards, and ISO 6780 with respect to weight rating and size.

It is a further objective of this invention to provide an easily recyclable product when pallet return is impracticable.

These and other objectives may be obtained by forming a corrugated paper pallet from stringers which are formed using the same cutting die and from top and bottom sheets which are cut to standard dimensions but may be of selected thickness as required for the load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a blank for a stringer showing cut and fold lines.

FIG. 2 illustrates the first folding sequence in the assembly of a cut stringer.

FIG. 3 shows the second folding sequence in the assembly of a cut stringer.

FIG. 4 is a perspective view of a folded stringer.

FIG. 5 is a partial cut-away showing final assembly of a corrugated paper pallet according to this invention.

DETAILED DESCRIPTION OF THE INVENTION

The pallet of this invention is constructed from standard corrugated paper and may use single or multiple thickness corrugated either coated or uncoated. The rating of the corrugated sheets may be the same or different but would be selected for specific types of use and standardized for that use. Unlike wood, corrugated is readily treated to impart resistance to water, moisture, grease and oil, and made flame retardant. This allows even smaller orders to be prepared for specific shipping conditions without need for ovens or pressure treatment equipment. For international shipment, no fumigation is required and the pallets weight less than equivalent wood pallets.

The pallet is made from three die cut corrugated sheets. One is a top surface which is a flat sheet having the final length and width dimensions of the pallet. The second is the bottom sheet, identical in length and width to the top sheet but which may be a single layer when the top is two or more layers.

For most uses in the U.S. and international markets, three stringers are used. In the preferred embodiment each stringer has the same configuration and may be cut from larger sheets of corrugated using a single die. FIG. 1 illustrates the preferred embodiment for forming a stringer. A blank 7 of appropriate thickness (weight) of corrugated sheet is cut from a larger sheet. Fold lines 15 and 17 divide the blank into a center section 9, a first side section 11 and a second side section 13. A third fold line 19 divides side section 11 to form a short flap 23. A fourth fold line 21 divides side 13 to form a wide flap 25.

Four cut-outs are made in side sections 11 and 13. Side cuts 27, 27 a, 27 b, 27 c, 27 d, 27 e, 27 f, 27 g and 27 h and end cuts 29, 29 a, 29 b, 29 c, and 29 d, end fold lines 31, 31 a, 31 b, 31 c, 31 d and middle fold lines 33, 33 a, 33 b, 33 c, 33 d result in four flaps having two distinct parts. Hinged flaps 35, 35 a, 35 b, 35 c, 35 d may be bent perpendicular to sections 11 and 13 and extension flaps 37, 37 a, 37 b, 37 c, 37 d may be bent perpendicularly from the hinged flaps.

FIG. 2 shows the first step in the folding sequence. Flaps 35 a, 35 b are folded out of the sections 11, 13 and the stringer section is folded to overlap side sections flap 25 outside shorter flap 23. The resultant rectangular tube is shown in FIG. 3, where the overlap of flap 25 over 23 is on the opposite side from center section 9. The flaps 37 are then tucked to become parallel to and within the opposite side section and flaps 35 a, 35 b are pressed inwardly to form an end to the rectangular tube section. The result is seen in FIG. 4 wherein the folded parts create open sides 41 in section 11 and 43 in section 13.

It is noted that before each flap is brought into contact with another, a suitable adhesive is applied. When three such sections are folded thusly, three identical stringer sections 51, 53, 55 are formed which may be aligned in parallel. These stringers are aligned on a bottom sheet 7 and adhered in place. It is noted that the overlapped section where flaps 23, 25 overlap is away from base 7. A top sheet 5 is then adhered to flap 25 to complete the construction.

The separation of the stringers between top and bottom sheets provides the traditional “2-way” entry for tines of a fork lift or pallet truck. Openings 41, 43 in each stringer allow entry of the tines at 90°, providing a full 4-way entry. Then manner in which the openings 41, 43 are created, through the folding of flaps 35, 37 vertical support is provided to the pallet and the double thickness at the overlap of flaps 23, 25 provides support at the point where the tines exert force upon lifting.

Adhesives are used as appropriate to the loads, intended uses (e.g. high humidity) and type of coating (if any) which is applied to the corrugated paper. A bar code or RFID may be applied at a suitable location on the pallet for pallet tracking.

It is expected that the die cut top and bottom sheets, and cut but not folded stringers, would be shipped flat from point of manufacture to point of assembly. At the point of assembly, a simple jig can be used to align the stringers as they are folded and adhered for accurate mounting of the top and bottom. Since no fasteners are required, the problem of snagging often encountered with wooden pallets is avoided, A smooth, flat surface with 100% coverage is advantageous for many operations since the stacked product maintains flat orientation until packaging is completed such as by stretch wrapping.

The pallets may be reused is used in a captive environment. When shipped long distances or subjected to abuse (e.g. ocean shipping) the pallets may be recycled at the destination as is conventional with all paperboard products.

INDUSTRIAL UTILITY

The corrugated pallet of this invention is light in weight, bug-free, strong and durable, easily assembled on-site to decrease component shipping costs. It may be reused or conveniently recycled into other paper products. 

1. A pallet constructed from corrugated paper and adhesive, comprising: at least two stringers; a top sheet; and a bottom sheet.
 2. A pallet according to claim 1 wherein each stringer is formed from identical corrugated blanks.
 3. A pallet according to claim 2 wherein each corrugated blank is die cut to form four flaps which depend from said blank.
 4. A pallet according to claim 3 wherein each of said flaps have a fold line between a base and an end.
 5. A pallet according to claim 1 wherein said stringer blanks have four fold lines parallel to the long axis of the blank, said fold lines dividing said blank into three adjacent central sections of equal width, a flanking narrow section and a flanking wide section.
 6. A pallet formed from corrugated paper made by the process of die cutting a corrugated paper blank to shape, forming four fold lines axial to the length of the blank to create three sections of equidistant width, one flanking narrow section and one flanking wide section, die cutting four flaps hinged from non-adjacent sections of equidistant width, said flaps being hinged from the blank and having fold lines across said flap at a distance from the hinge point equal to the width of one of said equidistant widths; folding said wide section over said narrow section to form a rectangular box section and adhering same in place, folding each of said flaps to cover a longitudinal opening in said box section; and adhering a top sheet and a bottom sheet to more than one box section aligned in parallel to each other. 